Metal Halide Lamps vs. Metal Arc Lamps

Hello.

This is my first post on this board, and I would like to ask a question about lighting. I currently have a 400w HPS/MH setup using a HPS ballast and a MH conversion bulb. A couple years ago I inherited a billboard sign company and about 3 dozen billboard sign lights. I was looking at them, and the bulbs (although a little larger) looked exactly like my Metal Halide conversion lamp. Now I haven't tore one of these heavy lights apart yet to find out the internals, but I am assuming that the ballast and everything is built right in.

Has anyone ever tried to veg with a metal arc lamp? When I looked at them online a couple places referred to them as a metal halide bulb. Will this work? They are in heavy billboard enclosures, and I have a feeling I am going to have to tear them apart to separate the ballast due to heat issues. Please let me know any thoughts. Below I have posted a link to the bulbs the lamps use. Thanks in advance!

http://www.greenelectricalsupply.com/sylvania-metalarc-m400-u-64490-metal-halide-bulbs.aspx





And here is a link to the lights themselves. They are Metrolux Sign Lights. If you click on the link, they are the ones with the domed glass on the bottom.

http://www.metrolux.com/bb/bb.html

Again, thanks for you help!

--RJ

Its a metal halide bulb, its fine for vegging, but not so great for flowering. It will still work though.

Thanks a lot for the reply, I am going to take one home tomorrow and start the tear down. If it is too complicated I am going to just leave it in the steel enclosure and get a big fan to blow on it. I was pretty sure that it would work, but there is no color temperature on the bulbs, and the ARC part kinda threw me off. Again, thanks for the response.

--RJ